Yarn about Conservative making comeback brings applause (5)
I believe the answer is:
eclat
'applause' is the definition.
(I've seen this in another clue)
'yarn about conservative making comeback' is the wordplay.
'yarn' becomes 'tale' (synonyms).
'about' is an insertion indicator.
'conservative' becomes 'C' (UK political abbreviation).
'making comeback' says the letters should be written backwards.
'tale' enclosing 'c' is 'talce'.
'talce' backwards is 'ECLAT'.
'brings' is the link.
(Other definitions for eclat that I've seen before include "Showy effect (Fr.)" , "Brilliant display or effect" , "Ostentation" , "Fame -- style" , "Cleat (anag.)" .)